@Dinh AaronMk
1) Communism generally removes individual incentives. Some people might think this is a benefit, since it eliminates greed and inequality, but it also destroys any sort of incentive to work hard. When you are compensated roughly the same regardless of how much you work, how strong you are, or how smart you are, why would anyone put in more than the minimal effort? Game theory works well here: if 1000 people work hard, everyone is 1000 times better off...until one person realizes he can do the bare minimum and still reap the rewards. Then the second, then the third, etc.
Most communists today aside from Tankies or even Nazbols are going to argue that removing individual incentives is a bad idea, looking back on the Soviet Union and comparing their policies to policies similar to that of say Yugoslavia. One of the lines I've heard used to argues against this very point isn't so much equality of outcomes but equality of access. But also the opportunity to own more of your own labor by awarding the workers with more a share of the final output of their production in a system that would be compared to today's profit sharing; the better their shop has performed in creating something that is purchased the more they are paid. There's a material incentive for the individual to see to that things get better.
And while you can pull the whole Game Theory thing on this with the one guy realizing he can coast on fumes while everyone burns through everything, that's already a thing in today's 'capitalist' workforce. When someone can disappear into the sea of numbers that is the employed and dodge their bosses well enough no one can tell how much this person did or did not do, so he gets paid the same rate as everyone else.
2) Removing private property also removes the incentive to maximize its use. When no one "owns" it no one will take care of it.
Hardly.
The point of a communalized farm for instance is to put everyone's resources into one basket so that everyone has more than they had as if they were going it alone. It's unlikely anyone is going to need a specific something all at the same time. And putting their head and effort together to maximize the profit of the commune they're as encouraged to do more and can consider and seek avenues to not only cut their own labor, but make more as worker-owners.
The process would be very much like automated factories, or the automated farms that are so much a thing in Texas and Oklahoma. But instead of forcing hundreds out of their family homes because there's no economic benefit to being there, and they'll have to try their hands at being a grocery store bag-man these individuals forced off still reap the benefits of the land by owning it together as a community. And having worked or presently working the land they already have more right to it than some asshole in a mansion in Houston's suburbs.
Present experiments in the US in cooperatively controlled businesses also lend support to this. While they might be slow in decision making because of consent of all - or most - of the employees there they honestly become more a haven of innovation and creativity than the regimented and impersonal world of traditional business structure; where while the top may make a quick decision, it may not be the right decision or the most innovative and is clouded by the ego of the individual on top.
While that seems small, US Company Gore
operates on a model very similar, and they're the company to make the high-tech fabrics that go into army coats, raincoats, fire-fighter's equipment, tubing for cars, and any high-tech material for computers and space. As I heard it in the book Tipping Point, even the owner identifies himself as an Associate, along with everyone else. Their organizational structure is very flat and democratic, and it's been working.
3) Prices. Prices are a perfect way to signal supply and demand. It is impossible for a central planner to determine the preferences of each individual in a nation...but free pricing can.
Again, not all communists are going to necessarily argue we can't have a market, at least not at the present pre-scarcity moment. The point of communism through socialism is to achieve a post-scarcity world where everyone owns without restraint of economic class the results of, and the means of production. In that one no single individual or group of individuals can hold the larger population hostage by leveeing unnecessary controls.
Anarcho-Mutualists, Communists, and Syndicalists would even argue to remove labor all together from the equation and let us live as artists.
In order to make any of these things work, you need a dictatorship to force people to do so. Not working hard enough? If the people's paradise doesn't motivate you, maybe the gulag will. Supply and demand not right? The government is forced to step in.
As I've included above, no you don't.
Going back to Gore one of the things that makes them unique is they split their factories every time the associate population rises above a hundred a fifty. As one associate put it, "When people start parking on the grass, we know it's time to split".
A community can manage itself to work towards a shared goal.
The above things may be doable on a small scale, but only if people have the choice to buy in. If you force entire nations to do so, it is going to be impossible to move out of the communist dictatorship; you will always need the force of law to make people not follow the "natural" psychology of supply and demand and incentives. I can't think of any practical way that the state will ever wither away.
Small scale is pretty much the point.